I see what OP is getting at and I have to agree. After all SP
was in part based on Romeo and Juliet. So I think both Flip and Lilac's theories are valid; if you want to look at it from a film-making perspective, the producers chose to make Simba overbearing so he fit the role of Juliet's father who was supposed to be cruel. However they had to soften up the plot a little bit because it is a Disney film, so Simba's personality was given a loving, fatherly touch. After all, it wouldn't be fun to see Simba harrass his daughter into marrying someone else or Kiara and Kovu murder themselves in a tombstone

It makes just as much sense if you think of it in terms of the actual storyline, because as others have said Simba may have simply been overprotective because Kiara was his only daughter and he was afraid he might lose her.